| abstract |
A process for tanning leathers including a pre-tanning step and a tanning step is provided. In the pre-tanning step leathers are treated with a cationic active agent including a quatemized ester of a fatty acid and triethanolamine, or mixtures thereof and, subsequently, with an anionic active agent including tannins vegetable extracts and a natural or synthetic dispersant selected from the group consisting of lignosulfonates, distillation stillages, sulfonated disulfonic polymers, sulfonated naphthalene polymers or mixtures thereof, to obtain leathers with a shrinkage temperature of at least 65° C. The pre-tanning and tanning steps do not include treatment with aldehydes or aldehyde donor compounds and/or with metal salts. |